Structural unit comprising heat exchanger and liquid separator

ABSTRACT

Described is a structural unit composed of a heat exchanger and a liquid separator, in particular for separating droplets from evaporated refrigerant, in particular for refrigeration and air conditioning systems, which structural unit is of compact design. According to the invention, in a pressure vessel ( 1 ) in which heat transfer plates ( 2 ) are arranged in a lower region and in which an upper region as a space for the separation of droplets from evaporated refrigerant is formed above the heat transfer plates ( 2 ) as a result of the arrangement of the heat transfer plates ( 2 ) in the lower region, the heat transfer plates are arranged substantially parallel to the longitudinal axis of the pressure vessel.

The invention refers to a structural unit comprising a heat exchanger having a plate-type heat exchanger and a liquid separator for separating droplets from evaporated refrigerant.

Heat exchangers comprising fully welded heat transfer plates in a pressure vessel are used in refrigeration and air conditioning systems and in other areas of application. The pressure vessel comprises external connections, for example for the inflow and outflow of a medium, which is to be temperature-controlled and which flows through the heat transfer plates, a connection for feeding a liquid refrigerant to the interior of the pressure vessel, and at least one connection for removing the refrigerant that has evaporated on the surfaces of the heat transfer plates due to the heat of the medium to be temperature-controlled.

Heat exchangers are often equipped with a pack of a multiplicity of pairs of round heat transfer plates, which are installed in the vessel in a pressure-stable manner.

The vessel must comprise at least one sufficiently stable, planar faceplate in order to support the pack of round heat transfer plates and absorb the high pressure acting on the round heat transfer plates.

The intrinsic mass of the pressure-proof vessel is therefore considerable.

Depending on the design, heat exchangers can be operated with full or partial counterflow and with one or more passes.

In addition to the heat exchanger, refrigeration and air conditioning systems comprise, in the refrigerant circuit, a separate vessel as the fluid separator disposed downstream of the heat exchanger, and a compressor, wherein the separate vessel and the compressor are connected to one another via pipework.

In the fluid separator, the droplets formed upon evaporation of a refrigerant on the heat transfer plates are separated from the gaseous phase in a known manner, basically using the force of gravity and optionally supported by special inserts. This separation is necessary in order to ensure that fluid in the form of droplets cannot be drawn into the downstream compressor, which is connected to the fluid separator, for the recondensation of the refrigerant, since the compressor can be damaged otherwise.

The usual design of heat exchangers and liquid separators in separate vessels requires projecting dimensions, large masses, elaborate designs of the necessary pipework for connecting the individual system parts, and a certain minimum volume of refrigerant.

The transport of such systems is also problematic, wherein complete assembly of a system in a specific case can be carried out only at the installation site.

The problem addressed by the invention is that of developing a structural unit comprising a heat exchanger having a plate-type heat exchanger and a liquid separator for separating droplets from evaporated refrigerant, in particular for refrigeration and air conditioning systems, which saves space, material, and refrigerant, and is compact.

The problem is solved by the features set forth in claim 1. Preferred developments will become apparent from the dependent claims.

A structural unit according to the invention combines a heat exchanger and a liquid separator, comprising a pressure vessel, in which heat transfer plates are disposed in a lower region, and in which an upper region is formed above the heat transfer plates as a space for the separation of droplets from evaporated refrigerant due to the arrangement of the heat transfer plates in the lower region, and wherein the heat transfer plates are disposed substantially parallel to the longitudinal axis of the pressure vessel.

Particular advantages of the invention are, in particular, the space-saving and material-saving design of the structural unit comprising the heat exchanger and the liquid separator with a particularly effective use of space due to the longitudinal arrangement of the heat transfer plates (i.e. axially parallel to the pressure vessel). Due to the design, the longitudinally disposed heat transfer plates advantageously utilize the lower region of the pressure vessel, require a relatively small “dead volume” underneath and on the sides of the heat transfer plates, and leave a relatively large volume in the pressure vessel open at the top, which is available for the liquid separation. The relatively large usable portion of the volume of the space for liquid separation makes it possible to obtain a smaller overall size of the pressure vessel. Combined, in particular, with the omission of a separate vessel for the liquid separator and the grouping of functionalities of heat exchanger and liquid separator in a common pressure vessel, a space-saving and material-saving device is therefore created, which also results in a substantial reduction of refrigerant.

Elaborate pipework between the heat exchanger and the liquid separator, which is common according to the prior art, is omitted, thereby promoting safe operation of a refrigeration or air conditioning system.

Due to the common pressure vessel and the optimized size thereof, combined with the omission of pipework, the expenditure required for thermal insulation is reduced. Furthermore, operation is made possible that is more energy-efficient than is the case when the heat exchanger and liquid separator are separate.

Due to the invention, the smaller size allows assembly, including the compressor, to be completed at the plant to form a total unit having dimensions within the common container dimensions, even for systems having such power, which previously could not be achieved when separate pressure vessels were used for the heat exchanger and the liquid separator. Transport expenditure is reduced and assembly effort at the installation site is reduced. In addition, a higher quality and safety standard can be ensured since pipework does not need to be created and production takes place in the plant.

Furthermore, the pressure vessel can comprise the usual elements, such as external stubs for the inflow and outflow of the media, and devices in the interior for regulating the inflow or outflow of the media, and, optionally, means for guiding or distributing a liquid refrigerant or means for guiding and distributing the vaporous refrigerant, for example by means of baffle plates, sieves, or labyrinths.

Further advantages result from the possible operation of the heat exchanger of the structural unit according to the invention in all usual manners, such as with partial or full counterflow, and with one or more passes.

In an advantageous variant, the pressure vessel is formed substantially of a tubular base body, which comprises torispherical heads welded to both sides thereof. This makes it possible to use standard components, thereby resulting in low-cost production.

In a preferred embodiment of the structural unit according to the invention, the heat transfer plates, which are disposed parallel to the longitudinal axis of the base body, are designed as at least one fully welded plate pack of plate pairs having the profiled heat transfer plates described in the document DE 10 2004 022 433 B4, which have a rectangular shape having head pieces delimited on both sides in an arc shape, wherein each head piece has a passage opening. The elongated, rectangular design of the plate pairs of the type described in DE 10 2004 022 433 B4, when arranged with the longer rectangular side axially parallel to the base body, results in a particularly effective implementation of the advantages of the invention, in particular the optimization of space and the resultant advantages. Advantageously, the heat exchange can take place with countercurrent. The arrangement of the heat transfer plates “standing” on the longitudinal side results in a short height.

In a further variant, the structural unit can comprise at least one further plate pack disposed above the first plate pack. The further plate pack advantageously comprises more plate pairs than the one underneath, thereby utilizing the greater internal width available at the installation point of the further plate pack due to the circular cross section of the tubular base body.

In further variants of the embodiment, it is feasible, in the case of an axial extension of the tubular base body, to dispose at least one further plate pack in the axial direction in the vicinity of the underside of the base body.

Further variants of the embodiment of additional plate packs in the axial direction in the base body, such as the arrangement of a plate pack that is offset with respect to the first plate packs by half the axial length thereof and that is broader in the radial direction of the tubular base body, are considered to be embodiments according to the invention.

Further advantages will become apparent from an embodiment of a cascadable arrangement of the plate packs. This means that the medium to be cooled flows through the plate packs in succession, thereby making it possible to optimize the heat transfer.

In a further embodiment, the pressure vessel is resistant to pressure that is greater than the possible pressure in the plate chamber. Due to this advantageous embodiment, if a leak occurs in the circuit of the medium to be cooled, in particular at the heat exchanger plates, the pressure that then acts on the pressure vessel is prevented from causing the pressure vessel to rupture and refrigerant, which is harmful to health, is prevented from escaping, even in the event of a breakdown.

Moreover, it is possible to arrange the described structural unit together with the compressor for compressing the evaporated refrigerant along with the required pipework in a frame, thereby resulting in a fully configured, completely assembled system that requires nothing more than to be connected to the connectors for the medium to be temperature-controlled.

The invention is described in greater detail as an exemplary embodiment. Therein

FIG. 1 shows a vertical sectional view of a structural unit in the axial direction

FIG. 2 shows a cross section of a structural unit

According to FIG. 1 and FIG. 2, a fully welded plate pack 2 of pairs of profiled heat transfer plates, which have a rectangular shape and head pieces delimited on both sides in an arc shape, as the structural unit comprising a heat exchanger having a plate-type heat exchanger and a liquid separator, is disposed in a pressure vessel 1, in the vicinity of the underside, parallel to the longitudinal axis thereof.

The pressure vessel 1 according to FIG. 1 substantially comprises a tubular base body 3, a first torispherical head 4, and a second torispherical head 5, which are welded to one another.

As depicted schematically in FIG. 2, the fully welded plate pack 2 is accommodated in a pressure-sealed manner between a left faceplate 6 and a right faceplate 7, which are connected in a non-positive manner by means of connecting elements 8.

FIGS. 1 and 2 also show a first connecting pipe 9 as the inlet for liquid refrigerant, a second connecting pipe 10 for siphoning off the evaporated refrigerant, an inlet pipe 11 and an outlet pipe 12 for a medium to be temperature-controlled in the plate pack 2, and an oil sump 13 having an oil extraction device 14.

Furthermore, connectors are provided for measurement means for ascertaining and regulating the fill level.

The use of torispherical heads 4; 5 for the pressure vessel 1 having the plate pack 2 disposed therein results in the advantage—compared to pressure vessels having at least one planar and heavy vessel jacket part for the pressure-proof accommodation of a heat exchanger having round plates—that additional volume is available for separating droplets from the evaporated refrigerant, and the dimensions of the pressure vessel 1 are reduced and the intrinsic mass thereof is lower. The pressure vessel is designed such that it can absorb a higher pressure than can be present in the plate chamber. Therefore, in the event of a rupture or leak, the pressure vessel is prevented from rupturing and safe system operation is ensured.

REFERENCE SIGNS USED

1 pressure vessel

2 heat transfer plates

3 tubular base body

4 first torispherical head

5 second torispherical head

6 left faceplate

7 right faceplate

8 connecting elements

9 first connecting pipe

10 second connecting pipe

11 inlet pipe

12 outlet pipe

13 oil sump

14 oil extraction device 

1. A structural unit comprising a heat exchanger and a liquid separator for separating droplets from evaporated refrigerant, in particular for refrigeration and air conditioning systems, having a pressure vessel (1) in which heat transfer plates (2) are disposed in a lower region, and in which an upper region is formed above the heat transfer plates (2) as a space for separating droplets from evaporated refrigerant due to the arrangement of the heat transfer plates (2) in the lower region, characterized in that the heat transfer plates are disposed substantially parallel to the longitudinal axis of the pressure vessel.
 2. The structural unit comprising a heat exchanger and a liquid separator according to claim 1, characterized in that the pressure vessel (1) is formed substantially of a tubular base body (3) and torispherical heads (4; 5) welded thereto on both sides.
 3. The structural unit comprising a heat exchanger and a liquid separator according to claim 1 or 2, characterized in that the heat transfer plates (2) are at least one fully welded plate pack of pairs of profiled heat transfer plates having a rectangular shape and head pieces delimited on both sides in an arc shape, wherein each head piece has a passage opening.
 4. The structural unit comprising a heat exchanger and a liquid separator according to claims 1 to 3, characterized in that at least one further plate pack, which has more plate pairs than the first plate pack, is disposed above the first plate pack.
 5. The structural unit comprising a heat exchanger and a liquid separator according to claims 1 to 4, characterized in that, in the axial extension of the tubular base body (3), at least one further plate pack is disposed in the axial direction after the first plate pack.
 6. The structural unit comprising a heat exchanger and a liquid separator according to claims 1 to 5, characterized in that a plurality of plate packs is disposed in a cascaded arrangement.
 7. The structural unit comprising a heat exchanger and a liquid separator according to claims 1 to 6, characterized in that the pressure vessel (1) is resistant to pressure greater than the possible operating pressure in the plate chamber of the heat exchanger plates.
 8. The structural unit comprising a heat exchanger and a liquid separator according to claims 1 to 7, characterized in that the structural unit, together with a compressor, is mounted via pipes in a frame as a complete system by means of a first connecting pipe (9) and a second connecting pipe (10) on the pressure vessel (1). 